The VPU is responsible for managing the core clock, usually under
direction from the bcm2835-cpufreq driver but not via the clk-bcm2835
driver. Since the core frequency can change without warning, it is
safer to report the maximum clock rate to users of the core clock -
I2C, SPI and the mini UART - to err on the safe side when calculating
clock divisors.
If the DT node for the clock driver includes a reference to the
firmware node, use the firmware API to query the maximum core clock
instead of reading the divider registers.
Prior to this patch, a "100KHz" I2C bus was sometimes clocked at about
160KHz. In particular, switching to the 4.9 kernel was likely to break
SenseHAT usage on a Pi3.
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
&usb {
power-domains = <&power RPI_POWER_DOMAIN_USB>;
};
&usb {
power-domains = <&power RPI_POWER_DOMAIN_USB>;
};
+
+&clocks {
+ firmware = <&firmware>;
+};
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <dt-bindings/clock/bcm2835.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <dt-bindings/clock/bcm2835.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
#define CM_PASSWORD 0x5a000000
#define CM_PASSWORD 0x5a000000
#define LOCK_TIMEOUT_NS 100000000
#define BCM2835_MAX_FB_RATE 1750000000u
#define LOCK_TIMEOUT_NS 100000000
#define BCM2835_MAX_FB_RATE 1750000000u
+#define VCMSG_ID_CORE_CLOCK 4
+
struct bcm2835_cprman {
struct device *dev;
void __iomem *regs;
struct bcm2835_cprman {
struct device *dev;
void __iomem *regs;
+ struct rpi_firmware *fw;
spinlock_t regs_lock; /* spinlock for all clocks */
const char *osc_name;
spinlock_t regs_lock; /* spinlock for all clocks */
const char *osc_name;
return bcm2835_clock_rate_from_divisor(clock, parent_rate, div);
}
return bcm2835_clock_rate_from_divisor(clock, parent_rate, div);
}
+static unsigned long bcm2835_clock_get_rate_vpu(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
+ struct bcm2835_cprman *cprman = clock->cprman;
+
+ if (cprman->fw) {
+ struct {
+ u32 id;
+ u32 val;
+ } packet;
+
+ packet.id = VCMSG_ID_CORE_CLOCK;
+ packet.val = 0;
+
+ if (!rpi_firmware_property(cprman->fw,
+ RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
+ &packet, sizeof(packet)))
+ return packet.val;
+ }
+
+ return bcm2835_clock_get_rate(hw, parent_rate);
+}
+
static void bcm2835_clock_wait_busy(struct bcm2835_clock *clock)
{
struct bcm2835_cprman *cprman = clock->cprman;
static void bcm2835_clock_wait_busy(struct bcm2835_clock *clock)
{
struct bcm2835_cprman *cprman = clock->cprman;
*/
static const struct clk_ops bcm2835_vpu_clock_clk_ops = {
.is_prepared = bcm2835_vpu_clock_is_on,
*/
static const struct clk_ops bcm2835_vpu_clock_clk_ops = {
.is_prepared = bcm2835_vpu_clock_is_on,
- .recalc_rate = bcm2835_clock_get_rate,
+ .recalc_rate = bcm2835_clock_get_rate_vpu,
.set_rate = bcm2835_clock_set_rate,
.determine_rate = bcm2835_clock_determine_rate,
.set_parent = bcm2835_clock_set_parent,
.set_rate = bcm2835_clock_set_rate,
.determine_rate = bcm2835_clock_determine_rate,
.set_parent = bcm2835_clock_set_parent,
struct resource *res;
const struct bcm2835_clk_desc *desc;
const size_t asize = ARRAY_SIZE(clk_desc_array);
struct resource *res;
const struct bcm2835_clk_desc *desc;
const size_t asize = ARRAY_SIZE(clk_desc_array);
+ struct device_node *fw_node;
size_t i;
u32 clk_id;
int ret;
size_t i;
u32 clk_id;
int ret;
if (IS_ERR(cprman->regs))
return PTR_ERR(cprman->regs);
if (IS_ERR(cprman->regs))
return PTR_ERR(cprman->regs);
+ fw_node = of_parse_phandle(dev->of_node, "firmware", 0);
+ if (fw_node) {
+ struct rpi_firmware *fw = rpi_firmware_get(NULL);
+ if (!fw)
+ return -EPROBE_DEFER;
+ cprman->fw = fw;
+ }
+
memset(bcm2835_clk_claimed, 0, sizeof(bcm2835_clk_claimed));
for (i = 0;
!of_property_read_u32_index(pdev->dev.of_node, "claim-clocks",
memset(bcm2835_clk_claimed, 0, sizeof(bcm2835_clk_claimed));
for (i = 0;
!of_property_read_u32_index(pdev->dev.of_node, "claim-clocks",